Many data centers, relying on coaxial infrastructure, are burdened and unable to keep up with the growing thirst for bandwidth posed by the multimedia and cloud services of the Internet, and by telecommunication in general. In place of traditional cables, optical fiber has become the primary and most researched transmission medium, be it long-distance or last-mile, for its compactness, low attenuation, high capacity, and immunity to electromagnetic interference.
Wavelength-division multiplexing is widely adopted in the optical communication industry to increase the per-fiber transmission rate and reduce material cost by aggregating signals of several wavelengths onto a single fiber. A wavelength-division multiplexer requires light of a given wavelength as input, often from a tunable laser, which is expensive considering the temperature and wavelength control modules attached to it.